The fall garden is for cold weather plants. Cold weather crops are usually planted the last week of June or first week of July. You want to time your crops to mature at the end of September. Look at your seed packet to see how many days it takes to mature. Count back from mature date (i.e. end of September) to know when to plant.
Fall Garden Crops
Carrots
Broccoli
Lettuce (you can start indoors if it is too hot, but don’t leave inside too long)
Spinach
Beets
Cabbage